Dimitrios Vrachatis

Non-invasive 24 hour ambulatory monitoring of aortic wave reflection and arterial stiffness by a novel oscillometric device: The first feasibility and reproducibility study

BACKGROUND Surrogates of aortic wave reflection and arterial stiffness, such as augmentation index (AIx), augmentation pressure, pulse wave velocity (PWV) and pulse pressure amplification (PPampl) are independent predictors of cardiovascular risk. A novel ambulatory, brachial cuff-based oscillometric device has been recently developed and validated, yielding 24-h assessment of the aforementioned parameters (Mobilo-O-Graph). Aim of this study was to investigate the feasibility and reproducibility of wave reflection and arterial stiffness estimation by pulse wave analysis using this device. METHODS Thirty treated or untreated hypertensives (mean age: 53.6 ± 11.6 years, 17 men) had test-retest 24-h monitoring one week apart using the test device. RESULTS Mean numbers of valid aortic readings per subject, between test and retest, were comparable. Approximately 12 aortic readings per subject (17%) were not feasible or valid. No differences were observed for any 24-h parameter between the two assessments. Bland-Altman plots showed no systemic difference, while the limits of agreement for each parameter indicated high reproducibility (AIx: -7.2 to 8.2%, AP: -3.7 to 4.1mm Hg, PWV: -0.39 to 0.41 m/s, PPampl: -0.08 to 0.06). This was further verified by intraclass correlation coefficients which were >0.8 for each parameter. CONCLUSIONS Non-invasive 24-h estimation of wave reflection and arterial stiffness indices, derived by the test device, appear to be highly reproducible. Future studies should investigate whether these measurements have additive prognostic value for cardiovascular risk stratification, beyond common brachial blood pressure measurements or single estimations of wave reflection and PWV at office settings.

Quantitative analysis of carotid plaque vasa vasorum by CEUS and correlation with histology after endarterectomy

BACKGROUND Intraplaque neovascularization and vasa vasorum (VV) proliferation contribute in the progression and rupture of atherosclerotic lesions. Contrast enhanced ultrasonography (CEUS) has been reported to attain data regarding intraplaque neovessels and VV. However, whether the detection of microbubbles by CEUS within atherosclerotic plaques truly represents microvessels is a point of concern. We aimed to evaluate stable and unstable carotid artery plaque (CAP) VV pattern by CEUS and its correlation with histology and immunochemistry. PATIENTS AND METHODS Patients with CAP scheduled for plaque endarterectomy were enrolled. CAP was initially identified by conventional ultrasonography and subsequently CEUS (harmonic ultrasound imaging with simultaneous intravenous contrast agent injection) was performed. The recorded image loops were evaluated by a semi-automated method. Plaque specimens were excised and underwent histological and immunochemical (for CD34, Vascular Endothelial Growth Factor, CD68 and CD3 antibodies) analysis. RESULTS Fourteen patients (67.6 ± 10.2 years, 10 males) with a 86.9 ± 11.5 % degree of carotid artery stenosis were evaluated. Histology showed that half of the plaques were unstable. Enhancement of plaque brightness on CEUS was significant for both stable and unstable plaque subgroups (p = 0.018 for both). Immunochemistry showed that microvessels, as assessed by CD34 antibody, were more dense in unstable vs. stable plaques (36.6 ± 17.4 vs. 13.0 ± 7.2 respectively, p = 0.002). However, correlation between plaque brigthness enhancement on CEUS and microvessel density was significant only for stable (r = 0.800, p = 0.031) plaques. CONCLUSIONS The identification of brightness enhacement during CEUS in carotid atherosclerotic plaques may not always reflect the presence of VV.

Predictive Factors of Vascular Complications after Transcatheter Aortic Valve Implantation in Patients Treated with a Default Percutaneous Strategy

BACKGROUND Percutaneous approach techniques with closure device after transcatheter aortic valve implantation (TAVI) have diminished vascular complications (VC). In this retrospective study, we will report incidence and angiographic factors predisposing to major VC in patients undergoing TAVI using Prostar® XL closure device as a default strategy. METHODS Consecutive patients, who underwent TAVI transfemorally using Prostar® XL, were evaluated for the incidence of VC according to VARC criteria. Using arterial angiography, the femoral-iliac arterial tortuosity was adjusted for large arterial diameters and expressed as the ratio total tortuosity/arterial diameter (TT/AD). Arterial calcification, the combination of angulation and atheromatosis at the puncture site and ideal puncture were evaluated too. In all patients, 30 days of follow-up was available. RESULTS Eighty-four patients (80.2 ± 5.86 years, 39 males [46.4%]), who were consecutively treated with the transfemoral approach, were evaluated. In patients with major VC (17/84 [20.23%]) comparing to those without, arterial calcification (11 [64.7%] vs. 8 [11.9%], P < 0.01) and the TT/AD (30.2 ± 11.25 vs. 22.06 ± 8.64, P < 0.01) were independent predictors. Ideal puncture was achieved more frequently among patients without VC comparing to those with major (94.1% vs. 70.6%, P = 0.01). Blood transfusions (1.48 ± 0.37 vs. 2.45 ± 0.59, P = 0.023) were more frequent among patients with major VC. Finally, minimum creatinin clearance after TAVI predicted all-cause 30-day mortality (P = 0.021). CONCLUSIONS Major VC after TAVI with the use of Prostar closure device can be predicted by arterial calcification at the puncture site and TT/AD ratio. Minimum creatinin clearance after TAVI predicted 30-day mortality.

CoreValve aortic bioprosthesis: repositioning techniques.

In a recent issue of JACC: Cardiovascular Interventions , Latib et al. ([1][1]) presented images of a technique for repositioning a just-implanted CoreValve (Medtronic, Minneapolis, Minnesota) aortic bioprosthesis with a snare. The “Snare” technique is a bail-out method, which has been

Effect of supine versus sitting position on noninvasive assessment of aortic pressure waveform: a randomized cross-over study.

Biomarkers derived noninvasively from the aortic blood pressure (BP) waveform provide information regarding cardiovascular (CV) risk independently of brachial BP (bBP). Although body position has significant impact on the assessment of bBP, its effect on aortic hemodynamics remains unknown. This study investigated the changes in both brachial and aortic hemodynamics, between the supine and sitting position. In this randomized cross-over study, the bBP and the aortic pressure waveform were assessed after a 5 min rest (sitting and supine in randomized order); aortic BP, pulse pressure (PP) amplification, augmentation index (AIx) and subendocardial viability index (SEVR) were assessed. Sixty-one subjects were examined (36 males, mean age 50±12 years). Mean BP did not differ between the sitting and supine position (110.8±13.7 vs 110.9±14.9, respectively, P=0.945). However, significant difference between the sitting and supine position in brachial PP (45.9±16.0 vs 52.6±15.6, respectively, P<0.001), aortic PP (36.7±15.2 vs 43.1±13.9, P<0.001), PP amplification (1.28±0.1 vs 1.23±0.1, P<0.001), AIx (26.9±11.9 vs 31.1±10.2, P<0.001) and SEVR (179.6±25.7 vs 161.2±25.8, P<0.001) were found. Review of the literature identified underestimation of the role of body position on aortic hemodynamics. In conclusion, increased PP in both the aorta and brachial artery were found in the supine compared to the sitting position. Reduced PP amplification and SEVR were further observed in the supine position, due to increased pressure wave reflections (AIx).

Residual Platelet Reactivity After Clopidogrel Loading in Patients With ST-Elevation Myocardial Infarction Undergoing an Unexpectedly Delayed Primary Percutaneous Coronary Intervention

BACKGROUND Residual platelet reactivity (RPR) after clopidogrel loading, measured by the VerifyNow assay, has been shown to predict 12-month clinical events in patients with acute coronary syndromes. However, links between coronary angiographic findings and outcome in patients with ST-elevation myocardial infarction (STEMI), with RPR have not been reported. We investigated whether RPR is associated with the amount of intracoronary thrombus burden (TB) in patients with STEMI undergoing unexpectedly-delayed primary percutaneous coronary intervention (pPCI). Moreover, we evaluated whether RPR might influence coronary flow and myocardial perfusion immediately post-pPCI. METHODS AND RESULTS The VerifyNow assay was used to determine RPR after clopidogrel loading, expressed in P2Y12-Reaction-Units (PRU). Intracoronary-TB was angiographically estimated and stratified as TB-Grade-A, -B and -C. Thrombolysis In Myocardial Infarction (TIMI) flow and Myocardial Blush (MB) were also estimated post-PCI. A total of 74 consecutive patients who presented with STEMI were enrolled in the study. Patients with greater TB presented significantly higher PRU-levels (174.1 ± 91.5, 196.23 ± 113.4 and 252.8 ± 107.8 for TB-Grade A, B and C, respectively; P=0.044). PRU-levels >251.5 were shown to predict Large-TB (LTB; TB-Grade-C) (sensitivity=57.9%; specificity=77.8%; P=0.014). Impaired TIMI-flow and MB after PCI were significantly associated with higher PRU-levels (P < 0.001). CONCLUSIONS Among the studied patients, those with a higher RPR after clopidogrel loading presented larger intracoronary TB, worse post-PCI myocardial flow and perfusion.

Letter to the EditorCoreValve Aortic Bioprosthesis: Repositioning Techniques

In a recent issue of JACC: Cardiovascular Interventions , Latib et al. ([1][1]) presented images of a technique for repositioning a just-implanted CoreValve (Medtronic, Minneapolis, Minnesota) aortic bioprosthesis with a snare. The “Snare” technique is a bail-out method, which has been

Inferior epigastric artery as a landmark for transfemoral TAVI. Optimizing vascular access

This study sought to investigate whether the site of common femoral artery (CFA) cannulation in regard to the inferior epigastric artery (IEA) is associated with the incidence of vascular complications in patients undergoing transfemoral aortic valve implantation (TAVI).

Mean arterial pressure values calculated using seven different methods and their associations with target organ deterioration in a single-center study of 1878 individuals.

To assess the differences among seven different methods for the calculation of mean arterial pressure (MAP) and to identify the formula that provides MAP values that are more closely associated with target organ deterioration as expressed by the carotid cross-sectional area (CSA), carotid-to-femoral pulse-wave velocity (cf-PWV) and left ventricular mass (LVM). The study population consisted of 1878 subjects who underwent noninvasive cardiovascular risk assessment. Blood pressure (BP) was assessed in all subjects, and MAP was calculated by direct oscillometry and six different formulas. Carotid artery ultrasound imaging was performed in 1628 subjects. The CSA of the right and left common carotid artery (CCA) were calculated and used as surrogates of arterial wall mass and hypertrophy. Aortic stiffness was evaluated in 1763 subjects by measuring the cf-PWV. Finally, 218 subjects underwent echocardiographic examination for the assessment of LVM. Among the examined methods of MAP calculation, the formula MAP1=[diastolic BP]+0.412 × [pulse pressure] yielded the strongest correlations with the LVM, cf-PWV and CSA of the right and left CCA, even after adjusting for age and gender. The MAP calculation using the 0.412 was superior compared with the traditional formula that uses the 0.33 for the discrimination of subjects with left ventricular and carotid wall hypertrophy, as well as subjects with increased aortic stiffness. MAP estimated with the 0.412 is better correlated with target organ deterioration compared with other formulas. Future studies are needed to explore the accuracy of these formulas for MAP estimation compared with direct intra-arterial BP measurement.

Biomarkers as a guide of medical treatment in cardiovascular diseases.

There is increasing interest in utilizing novel markers of cardiovascular disease risk and consequently, there is a need to assess the value of their use. In this paper, we will review the role of biomarkers in acute coronary syndromes, heart failure and risk stratification for cardiovascular events as guide for treatment scribing. In particular, high sensitivity assays for troponin evaluation detect with greater precision patients with elevated troponin. Therefore, direct and appropriate management is succeeded in these patients with reduction of complications due to earlier treatment, as well. Regarding heart failure, randomized trials that have evaluated biomarker guided treatment approach have not succeeded in establishing specific results for natriuretic peptides (BNP, NT-proBNP) use in terms of therapy guidance. Apart from them, a variety of novel or already used biomarkers, have been tested by small trials for heart failure management, without however, managing to dominate in every day care. Finally, as far as risk stratification for cardiovascular events is concerned, hsCRP has proved to be a strong but doubted biomarker. Therefore, lifestyle and behavioral modification remain the cornerstone of primary prevention.